SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 7 days to 20 May 2024: Chile 55.9 µg/m³, India 44.0 µg/m³ and Pakistan 38.1 µg/m³.
- 1Chile44 cities55.9
- 2India4 cities44.0
- 3Pakistan4 cities38.1
- 4Malta5 cities31.4
- 5China3 cities27.6
- 6Laos3 cities22.8
- 7Mexico10 cities22.8
- 8Peru12 cities20.5
- 9Thailand79 cities19.3
- 10Taiwan43 cities16.7
- 11Greece7 cities15.5
- 12New Zealand5 cities14.1
- 13Hong Kong9 cities13.2
- 14South Korea141 cities12.5
- 15The Netherlands36 cities12.5
- 16Belgium44 cities12.4
- 17North Macedonia9 cities11.3
- 18Latvia4 cities11.0
- 19Italy36 cities10.3
- 20Singapore5 cities10.3
+ 28 more countries, 10.1 µg/m³ and below
- 39United States793 cities6.1
Not counted on this day, too few cities measured: Luxembourg since 19 May 2024, Austria since 10 May 2024, Bosnia and Herzegovina since 26 Apr 2024 and Montenegro since 22 Mar 2024.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.